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A Reboot for Flywheel Design

Flywheel energy storage system design has been revised by a Lancaster University, UK, student to retain energy kinetically in a levitated floating mass. The rotor is permanently levitated and requires no additional control mechanisms, maintenance, or user input. The football-sized unit is considered ideal for domestic uses and can be scaled up to industrial applications by stacking many units together on the same network to provide a bigger energy store. In contrast to batteries, the flywheel system boasts a 30-year service life and a higher ramping rate.

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Re: A Reboot for Flywheel Design

I agree that it would be nice to know how permanent levitation can be accomplished. Then again this unknown levitation technique might be precisely the crux of a yet to be approved patent.

100,000+ RPM is pretty darn fast spin for any macroscopic mass, particularly one that will store a Megawatt of power. Lancaster resides at 54° N. I wonder how much of the 30 year expected lifetime will be due to the lower precession torques from being closer to the Earth's axis?

Re: A Reboot for Flywheel Design

09/20/2016 2:12 PM

Maybe the levitation is superconductor. (If that's it, I haven't heard of any room temperature superconductors, so I would hope they don't run out of liquid N2 at 144000 rpm.)

I would hope they would be gimbaled and so no reaction torques, and if they are fixed position, they could be oriented so the axis of rotation is parallel to the earth's. (I can't shake the mental image of footballs precessing around daily!)

Re: A Reboot for Flywheel Design

09/25/2016 12:11 PM

the axis of the vertically mounted rotor must have a sizable rare earth magnet stuck to the bottom end with another on opposing magnet fixed at the base. Add the right bearings and perma-lift-levitation.

I don't think I thing a basketball sized unit would double the potential and triple the efficiency.

Do I hear beach ball?

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I have one of these and they're fun to play with, but the "sweet spot" is pretty tight and the weight has to be carefully adjusted for it to be stable. It's only stable within a certain speed range. It can be spun up (and I assume spun down, removing energy) with a magnetic field that couples with the slight precession.

The toy top is essentially a permanent magnetic ring and corresponding magnetic base plate with a ring or alternate geometric configuration. Functional parameters, such as the top rotation rate or top weighting, are stringent. Employing principles of the magnetic field and gyroscopic stabilization, the Levitron induces levitation in its top through a series of interactive steps. The levitated top's stabilizing rotation undergoes natural, gradual slowing, so that the levitation phenomenon fails within four minutes unless external power is supplied to sustain rotation.

To levitate the top, a plastic plate is placed on top of the magnetic base, and the top is spun on the plate at between 25-50 rotations per second (1500-3000 rpm). If too slow, the top falls over and slides off sideways; if too fast it does not orient itself to follow magnetic flux as it moves, and slides off. Since it can be difficult to spin the top fast enough by hand, Creative Gifts makes a battery-powered, hand held device to spin the top with an electric motor. Next, the plate is lifted by hand until, if conditions are right, the top rises above it to an equilibrium point. The top must also be weighted with washers of various sizes supplied in the kit. If too heavy it will not rise above the plate; if too light it flies off.[3]

After a few minutes, the top falls when air friction slows it below the critical speed. Air temperature, air currents, ground vibration, and power source interruptions also alter the delicate equilibrium necessary to keep the top stable. More expensive laboratory versions can sustain a levitating top indefinitely by sustaining the top rotation actively compensating for aberrations in rotation. The makers of the Levitron have developed a "Perpetuator", which sits under the Levitron and sends out an additional magnetic pulse. The additional force nudges the spinning top enough to maintain a constant speed. With a constant speed, and with the Levitron perfectly level, the Levitron top can spin for longer periods of time."

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